151
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Hehar H, Ma I, Mychasiuk R. Intergenerational Transmission of Paternal Epigenetic Marks: Mechanisms Influencing Susceptibility to Post-Concussion Symptomology in a Rodent Model. Sci Rep 2017; 7:7171. [PMID: 28769086 PMCID: PMC5541091 DOI: 10.1038/s41598-017-07784-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 06/30/2017] [Indexed: 01/29/2023] Open
Abstract
Epigenetic transmission of phenotypic variance has been linked to paternal experiences prior to conception and during perinatal development. Previous reports indicate that paternal experiences increase phenotypic heterogeneity and may contribute to offspring susceptibility to post-concussive symptomology. This study sought to determine if epigenetic tags, specifically DNA methylation of promoter regions, are transmitted from rodent fathers to their sons. Using MethyLight, promoter methylation of specific genes involved in recovery from concussion and brain plasticity were analyzed in sperm and brain tissue. Promoter methylation in sperm differed based on paternal experience. Differences in methylation were often identified in both the sperm and brain tissue obtained from their sons, demonstrating transmission of epigenetic tags. For certain genes, methylation in the sperm was altered following a concussion suggesting that a history of brain injury may influence paternal transmission of traits. As telomere length is paternally inherited and linked to neurological health, this study examined paternally derived differences in telomere length, in both sperm and brain. Telomere length was consistent between fathers and their sons, and between brain and sperm, with the exception of the older fathers. Older fathers exhibited increased sperm telomere length, which was not evident in sperm or brain of their sons.
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Affiliation(s)
- Harleen Hehar
- Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, University of Calgary, Department of Psychology, Calgary, Alberta, Canada
| | - Irene Ma
- Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, University of Calgary, Department of Psychology, Calgary, Alberta, Canada
| | - Richelle Mychasiuk
- Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, University of Calgary, Department of Psychology, Calgary, Alberta, Canada.
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152
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Wood ML, Royle NJ. Chromosomally Integrated Human Herpesvirus 6: Models of Viral Genome Release from the Telomere and Impacts on Human Health. Viruses 2017; 9:E184. [PMID: 28704957 PMCID: PMC5537676 DOI: 10.3390/v9070184] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 06/30/2017] [Accepted: 07/05/2017] [Indexed: 12/11/2022] Open
Abstract
Human herpesvirus 6A and 6B, alongside some other herpesviruses, have the striking capacity to integrate into telomeres, the terminal repeated regions of chromosomes. The chromosomally integrated forms, ciHHV-6A and ciHHV-6B, are proposed to be a state of latency and it has been shown that they can both be inherited if integration occurs in the germ line. The first step in full viral reactivation must be the release of the integrated viral genome from the telomere and here we propose various models of this release involving transcription of the viral genome, replication fork collapse, and t-circle mediated release. In this review, we also discuss the relationship between ciHHV-6 and the telomere carrying the insertion, particularly how the presence and subsequent partial or complete release of the ciHHV-6 genome may affect telomere dynamics and the risk of disease.
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Affiliation(s)
- Michael L Wood
- Department of Genetics, University of Leicester, University Road, Leicester LE1 7RH, UK.
| | - Nicola J Royle
- Department of Genetics, University of Leicester, University Road, Leicester LE1 7RH, UK.
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153
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Booth SA, Charchar FJ. Cardiac telomere length in heart development, function, and disease. Physiol Genomics 2017; 49:368-384. [DOI: 10.1152/physiolgenomics.00024.2017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Telomeres are repetitive nucleoprotein structures at chromosome ends, and a decrease in the number of these repeats, known as a reduction in telomere length (TL), triggers cellular senescence and apoptosis. Heart disease, the worldwide leading cause of death, often results from the loss of cardiac cells, which could be explained by decreases in TL. Due to the cell-specific regulation of TL, this review focuses on studies that have measured telomeres in heart cells and critically assesses the relationship between cardiac TL and heart function. There are several lines of evidence that have identified rapid changes in cardiac TL during the onset and progression of heart disease as well as at critical stages of development. There are also many factors, such as the loss of telomeric proteins, oxidative stress, and hypoxia, that decrease cardiac TL and heart function. In contrast, antioxidants, calorie restriction, and exercise can prevent both cardiac telomere attrition and the progression of heart disease. TL in the heart is also indicative of proliferative potential and could facilitate the identification of cells suitable for cardiac rejuvenation. Although these findings highlight the involvement of TL in heart function, there are important questions regarding the validity of animal models, as well as several confounding factors, that need to be considered when interpreting results and planning future research. With these in mind, elucidating the telomeric mechanisms involved in heart development and the transition to disease holds promise to prevent cardiac dysfunction and potentiate regeneration after injury.
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Affiliation(s)
- S. A. Booth
- Faculty of Science and Technology, School of Applied and Biomedical Sciences, Federation University Australia, Balllarat, Australia
| | - F. J. Charchar
- Faculty of Science and Technology, School of Applied and Biomedical Sciences, Federation University Australia, Balllarat, Australia
- Department of Physiology, The University of Melbourne, Melbourne, Australia; and
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
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154
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Abstract
Bacteria and viruses possess circular DNA, whereas eukaryotes with typically very large DNA molecules have had to evolve into linear chromosomes to circumvent the problem of supercoiling circular DNA of that size. Consequently, such organisms possess telomeres to cap chromosome ends. Telomeres are essentially tandem repeats of any DNA sequence that are present at the ends of chromosomes. Their biology has been an enigmatic one, involving various molecules interacting dynamically in an evolutionarily well-trimmed fashion. Telomeres range from canonical hexameric repeats in most eukaryotes to unimaginably random retrotransposons, which attach to chromosome ends and reverse-transcribe to DNA in some plants and insects. Telomeres invariably associate with specialised protein complexes that envelop it, also regulating access of the ends to legitimate enzymes involved in telomere metabolism. They also transcribe into repetitive RNA which also seems to be playing significant roles in telomere maintenance. Telomeres thus form the intersection of DNA, protein, and RNA molecules acting in concert to maintain chromosome integrity. Telomere biology is emerging to appear ever more complex than previously envisaged, with the continual discovery of more molecules and interplays at the telomeres. This review also includes a section dedicated to the history of telomere biology, and intends to target the scientific audience new to the field by rendering an understanding of the phenomenon of chromosome end protection at large, with more emphasis on the biology of human telomeres. The review provides an update on the field and mentions the questions that need to be addressed.
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Affiliation(s)
- Shriram Venkatesan
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597 Singapore, Singapore.
| | - Aik Kia Khaw
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597 Singapore, Singapore.
- Clinical Research Unit, Khoo Teck Puat Hospital, 768828 Singapore, Singapore.
| | - Manoor Prakash Hande
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597 Singapore, Singapore.
- Tembusu College, National University of Singapore, 138598 Singapore, Singapore.
- VIT University, Vellore 632014, India.
- Mangalore University, Mangalore 574199, India.
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155
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Theodoris CV, Mourkioti F, Huang Y, Ranade SS, Liu L, Blau HM, Srivastava D. Long telomeres protect against age-dependent cardiac disease caused by NOTCH1 haploinsufficiency. J Clin Invest 2017; 127:1683-1688. [PMID: 28346225 DOI: 10.1172/jci90338] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 01/31/2017] [Indexed: 01/04/2023] Open
Abstract
Diseases caused by gene haploinsufficiency in humans commonly lack a phenotype in mice that are heterozygous for the orthologous factor, impeding the study of complex phenotypes and critically limiting the discovery of therapeutics. Laboratory mice have longer telomeres relative to humans, potentially protecting against age-related disease caused by haploinsufficiency. Here, we demonstrate that telomere shortening in NOTCH1-haploinsufficient mice is sufficient to elicit age-dependent cardiovascular disease involving premature calcification of the aortic valve, a phenotype that closely mimics human disease caused by NOTCH1 haploinsufficiency. Furthermore, progressive telomere shortening correlated with severity of disease, causing cardiac valve and septal disease in the neonate that was similar to the range of valve disease observed within human families. Genes that were dysregulated due to NOTCH1 haploinsufficiency in mice with shortened telomeres were concordant with proosteoblast and proinflammatory gene network alterations in human NOTCH1 heterozygous endothelial cells. These dysregulated genes were enriched for telomere-contacting promoters, suggesting a potential mechanism for telomere-dependent regulation of homeostatic gene expression. These findings reveal a critical role for telomere length in a mouse model of age-dependent human disease and provide an in vivo model in which to test therapeutic candidates targeting the progression of aortic valve disease.
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156
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Ludlow AT, Gratidão L, Ludlow LW, Spangenburg EE, Roth SM. Acute exercise activates p38 MAPK and increases the expression of telomere-protective genes in cardiac muscle. Exp Physiol 2017; 102:397-410. [PMID: 28166612 DOI: 10.1113/ep086189] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 01/20/2017] [Indexed: 12/14/2022]
Abstract
NEW FINDINGS What is the central question of this study? A positive association between telomere length and exercise training has been shown in cardiac tissue of mice. It is currently unknown how each bout of exercise influences telomere-length-regulating proteins. We sought to determine how a bout of exercise altered the expression of telomere-length-regulating genes and a related signalling pathway in cardiac tissue of mice. What is the main finding and its importance? Acute exercise altered the expression of telomere-length-regulating genes in cardiac tissue and might be related to altered mitogen-activated protein kinase signalling. These findings are important in understanding how exercise provides a cardioprotective phenotype with ageing. Age is the greatest risk factor for cardiovascular disease. Telomere length is shorter in the hearts of aged mice compared with young mice, and short telomere length has been associated with an increased risk of cardiovascular disease. One year of voluntary wheel-running exercise attenuates the age-associated loss of telomere length and results in altered gene expression of telomere-length-maintaining and genome-stabilizing proteins in heart tissue of mice. Understanding the early adaptive response of the heart to an endurance exercise bout is paramount to understanding the impact of endurance exercise on heart tissue and cells. To this end, we studied mice before (BL), immediately after (TP1) and 1 h after a treadmill running bout (TP2). We measured the changes in expression of telomere-related genes (shelterin components), DNA-damage-sensing (p53 and Chk2) and DNA-repair genes (Ku70 and Ku80) and mitogen-activated protein kinase (MAPK) signalling. The TP1 animals had increased TRF1 and TRF2 protein and mRNA levels, greater expression of DNA-repair and -response genes (Chk2 and Ku80) and greater protein content of phosphorylated p38 MAPK compared with both BL and TP2 animals. These data provide insights into how physiological stressors remodel the heart tissue and how an early adaptive response mediated by exercise may be maintaining telomere length and/or stabilizing the heart genome through the upregulation of telomere-protective genes.
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Affiliation(s)
- Andrew T Ludlow
- Department of Kinesiology, School of Public Health, University of Maryland at College Park, College Park, MD, USA.,Department of Cell Biology, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Laila Gratidão
- Department of Kinesiology, School of Public Health, University of Maryland at College Park, College Park, MD, USA.,Kinesiology Graduate Program, Catholic University of Brasilia, Brasilia, Brazil
| | - Lindsay W Ludlow
- Department of Kinesiology, School of Public Health, University of Maryland at College Park, College Park, MD, USA.,Department of Applied Physiology, Southern Methodist University, Dallas, TX, USA
| | - Espen E Spangenburg
- Department of Physiology, Brody School of Medicine, East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, USA
| | - Stephen M Roth
- Department of Kinesiology, School of Public Health, University of Maryland at College Park, College Park, MD, USA
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157
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Martínez P, Blasco MA. Telomere-driven diseases and telomere-targeting therapies. J Cell Biol 2017; 216:875-887. [PMID: 28254828 PMCID: PMC5379954 DOI: 10.1083/jcb.201610111] [Citation(s) in RCA: 171] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/03/2017] [Accepted: 01/09/2017] [Indexed: 01/19/2023] Open
Abstract
Martínez and Blasco review the molecular mechanisms underlying diseases associated with telomere dysfunction, including telomeropathies, age-related disorders, and cancer. Current and future therapeutic strategies to treat and prevent these diseases, including preclinical development of telomere-targeted therapies using mouse models, are discussed. Telomeres, the protective ends of linear chromosomes, shorten throughout an individual’s lifetime. Telomere shortening is proposed to be a primary molecular cause of aging. Short telomeres block the proliferative capacity of stem cells, affecting their potential to regenerate tissues, and trigger the development of age-associated diseases. Mutations in telomere maintenance genes are associated with pathologies referred to as telomere syndromes, including Hoyeraal-Hreidarsson syndrome, dyskeratosis congenita, pulmonary fibrosis, aplastic anemia, and liver fibrosis. Telomere shortening induces chromosomal instability that, in the absence of functional tumor suppressor genes, can contribute to tumorigenesis. In addition, mutations in telomere length maintenance genes and in shelterin components, the protein complex that protects telomeres, have been found to be associated with different types of cancer. These observations have encouraged the development of therapeutic strategies to treat and prevent telomere-associated diseases, namely aging-related diseases, including cancer. Here we review the molecular mechanisms underlying telomere-driven diseases and highlight recent advances in the preclinical development of telomere-targeted therapies using mouse models.
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Affiliation(s)
- Paula Martínez
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre, Madrid E-28029, Spain
| | - Maria A Blasco
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre, Madrid E-28029, Spain
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158
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Zou Y, Leong W, Yao M, Hu X, Lu S, Zhu X, Chen L, Tong J, Shi J, Gilson E, Ye J, Lu Y. Test anxiety and telomere length: Academic stress in adolescents may not cause rapid telomere erosion. Oncotarget 2017; 8:10836-10844. [PMID: 28122333 PMCID: PMC5355227 DOI: 10.18632/oncotarget.14793] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 01/11/2017] [Indexed: 12/19/2022] Open
Abstract
Academic stress (AS) is one of the most important health problems experienced by students, but no biomarker of the potential psychological or physical problems associated with AS has yet been identified. As several cross-sectional studies have shown that psychiatric conditions accelerate aging and shorten telomere length (TL), we explored whether AS affected TL.Between June 2014 and July 2014, we recruited 200 junior high school students with imminent final examinations for participation in this study. The students were divided into three subgroups (mild, moderate, and severe anxiety) using the Sarason Test Anxiety Scale (TAS). Saliva samples were collected for TL measurement via quantitative polymerase chain reaction (qPCR).Students from both a specialized and a general school suffered from anxiety (p > 0.05). A total 35% had severe anxiety (score: 26.09±3.87), 33% had moderate anxiety (16.98±2.64), and 32% had mild anxiety (7.89±1.92). The TAS values differed significantly (p < 0.05) among the three subgroups, but the TLs of saliva cells differed only slightly (p > 0.05): 1.14±0.46 for those with severe anxiety, 1.02±0.40 for those with moderate anxiety, and 1.12±0.45 for those with mild anxiety.Previous reports have found that AS is very common in Asian adolescents. We found no immediate telomere shortening in adolescents with AS. Longitudinal observations are required to determine if TL is affected by AS.
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Affiliation(s)
- Yaru Zou
- International Laboratory in Hematology and Cancer, Shanghai Jiao Tong University School of Medicine/Ruijin Hospital/CNRS/INSERM/Nice University, Pôle Sino-Français de Recherche en Sciences du Vivant et Génomique, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Emergency Department, Shanghai Ruijin Hospital North, Shanghai, China.,Dermatology Department, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Waiian Leong
- International Laboratory in Hematology and Cancer, Shanghai Jiao Tong University School of Medicine/Ruijin Hospital/CNRS/INSERM/Nice University, Pôle Sino-Français de Recherche en Sciences du Vivant et Génomique, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Emergency Department, Shanghai Ruijin Hospital North, Shanghai, China.,Emergency Department, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Mingling Yao
- International Laboratory in Hematology and Cancer, Shanghai Jiao Tong University School of Medicine/Ruijin Hospital/CNRS/INSERM/Nice University, Pôle Sino-Français de Recherche en Sciences du Vivant et Génomique, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Emergency Department, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xuefei Hu
- International Laboratory in Hematology and Cancer, Shanghai Jiao Tong University School of Medicine/Ruijin Hospital/CNRS/INSERM/Nice University, Pôle Sino-Français de Recherche en Sciences du Vivant et Génomique, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,School of Life Science, Eastern China Normal University, Shanghai, China
| | - Sixiao Lu
- Xiangming High School, Shanghai, China
| | - Xiaowei Zhu
- International Laboratory in Hematology and Cancer, Shanghai Jiao Tong University School of Medicine/Ruijin Hospital/CNRS/INSERM/Nice University, Pôle Sino-Français de Recherche en Sciences du Vivant et Génomique, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Emergency Department, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lianxiang Chen
- International Laboratory in Hematology and Cancer, Shanghai Jiao Tong University School of Medicine/Ruijin Hospital/CNRS/INSERM/Nice University, Pôle Sino-Français de Recherche en Sciences du Vivant et Génomique, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Emergency Department, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jianjing Tong
- Exclusive Medical Care Center, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jingyi Shi
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Eric Gilson
- International Laboratory in Hematology and Cancer, Shanghai Jiao Tong University School of Medicine/Ruijin Hospital/CNRS/INSERM/Nice University, Pôle Sino-Français de Recherche en Sciences du Vivant et Génomique, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Université Côte d'Azur, CNRS, INSERM, IRCAN, Faculty of Medicine, Nice, France.,Department of Medical Genetics, CHU Nice, France
| | - Jing Ye
- International Laboratory in Hematology and Cancer, Shanghai Jiao Tong University School of Medicine/Ruijin Hospital/CNRS/INSERM/Nice University, Pôle Sino-Français de Recherche en Sciences du Vivant et Génomique, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Emergency Department, Shanghai Ruijin Hospital North, Shanghai, China.,Emergency Department, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yiming Lu
- International Laboratory in Hematology and Cancer, Shanghai Jiao Tong University School of Medicine/Ruijin Hospital/CNRS/INSERM/Nice University, Pôle Sino-Français de Recherche en Sciences du Vivant et Génomique, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Emergency Department, Shanghai Ruijin Hospital North, Shanghai, China.,Emergency Department, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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159
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Fane M, Harris L, Smith AG, Piper M. Nuclear factor one transcription factors as epigenetic regulators in cancer. Int J Cancer 2017; 140:2634-2641. [PMID: 28076901 DOI: 10.1002/ijc.30603] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 12/12/2016] [Accepted: 12/29/2016] [Indexed: 12/23/2022]
Abstract
Tumour heterogeneity poses a distinct obstacle to therapeutic intervention. While the initiation of tumours across various physiological systems is frequently associated with signature mutations in genes that drive proliferation and bypass senescence, increasing evidence suggests that tumour progression and clonal diversity is driven at an epigenetic level. The tumour microenvironment plays a key role in driving diversity as cells adapt to demands imposed during tumour growth, and is thought to drive certain subpopulations back to a stem cell-like state. This stem cell-like phenotype primes tumour cells to react to external cues via the use of developmental pathways that facilitate changes in proliferation, migration and invasion. Because the dynamism of this stem cell-like state requires constant chromatin remodelling and rapid alterations at regulatory elements, it is of great therapeutic interest to identify the cell-intrinsic factors that confer these epigenetic changes that drive tumour progression. The nuclear factor one (NFI) family are transcription factors that play an important role in the development of many mammalian organ systems. While all four family members have been shown to act as either oncogenes or tumour suppressors across various cancer models, evidence has emerged implicating them as key epigenetic regulators during development and within tumours. Notably, NFIs have also been shown to regulate chromatin accessibility at distal regulatory elements that drive tumour cell dissemination and metastasis. Here we summarize the role of the NFIs in cancer, focusing largely on the potential mechanisms associated with chromatin remodelling and epigenetic modulation of gene expression.
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Affiliation(s)
- Mitchell Fane
- The School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia.,School of Biomedical Sciences, Institute of Health and Biomedical Innovation at the Translational Research Institute, Queensland University of Technology, Woolloongabba, QLD, Australia
| | - Lachlan Harris
- The School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Aaron G Smith
- School of Biomedical Sciences, Institute of Health and Biomedical Innovation at the Translational Research Institute, Queensland University of Technology, Woolloongabba, QLD, Australia.,Dermatology Research Centre, The University of Queensland, School of Medicine, Translational Research Institute, Brisbane, QLD, Australia
| | - Michael Piper
- The School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
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160
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Barthel FP, Wei W, Tang M, Martinez-Ledesma E, Hu X, Amin SB, Akdemir KC, Seth S, Song X, Wang Q, Lichtenberg T, Hu J, Zhang J, Zheng S, Verhaak RGW. Systematic analysis of telomere length and somatic alterations in 31 cancer types. Nat Genet 2017; 49:349-357. [PMID: 28135248 DOI: 10.1038/ng.3781] [Citation(s) in RCA: 409] [Impact Index Per Article: 58.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 01/04/2017] [Indexed: 12/13/2022]
Abstract
Cancer cells survive cellular crisis through telomere maintenance mechanisms. We report telomere lengths in 18,430 samples, including tumors and non-neoplastic samples, across 31 cancer types. Telomeres were shorter in tumors than in normal tissues and longer in sarcomas and gliomas than in other cancers. Among 6,835 cancers, 73% expressed telomerase reverse transcriptase (TERT), which was associated with TERT point mutations, rearrangements, DNA amplifications and transcript fusions and predictive of telomerase activity. TERT promoter methylation provided an additional deregulatory TERT expression mechanism. Five percent of cases, characterized by undetectable TERT expression and alterations in ATRX or DAXX, demonstrated elongated telomeres and increased telomeric repeat-containing RNA (TERRA). The remaining 22% of tumors neither expressed TERT nor harbored alterations in ATRX or DAXX. In this group, telomere length positively correlated with TP53 and RB1 mutations. Our analysis integrates TERT abnormalities, telomerase activity and genomic alterations with telomere length in cancer.
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Affiliation(s)
- Floris P Barthel
- The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut, USA.,Oncology Graduate School Amsterdam, VU University Medical Center, Amsterdam, the Netherlands.,Department of Genomic Medicine, the University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Wei Wei
- Department of Biostatistics, the University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Ming Tang
- Department of Genomic Medicine, the University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Emmanuel Martinez-Ledesma
- Department of Genomic Medicine, the University of Texas MD Anderson Cancer Center, Houston, Texas, USA.,Department of Neuro-Oncology, the University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Xin Hu
- Department of Genomic Medicine, the University of Texas MD Anderson Cancer Center, Houston, Texas, USA.,Program in Biostatistics, Bioinformatics, and Systems Biology, the University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas, USA
| | - Samirkumar B Amin
- Department of Genomic Medicine, the University of Texas MD Anderson Cancer Center, Houston, Texas, USA.,Graduate Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas, USA
| | - Kadir C Akdemir
- Department of Genomic Medicine, the University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Sahil Seth
- Institute for Applied Cancer Science, the University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Xingzhi Song
- Institute for Applied Cancer Science, the University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Qianghu Wang
- Department of Genomic Medicine, the University of Texas MD Anderson Cancer Center, Houston, Texas, USA.,Department of Bioinformatics and Computational Biology, the University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Tara Lichtenberg
- Biopathology Center, Nationwide Children's Hospital, Columbus, Ohio, USA
| | - Jian Hu
- Department of Cancer Biology, the University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Jianhua Zhang
- Institute for Applied Cancer Science, the University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Siyuan Zheng
- Department of Genomic Medicine, the University of Texas MD Anderson Cancer Center, Houston, Texas, USA.,Department of Neuro-Oncology, the University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Roel G W Verhaak
- The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut, USA.,Department of Genomic Medicine, the University of Texas MD Anderson Cancer Center, Houston, Texas, USA.,Department of Bioinformatics and Computational Biology, the University of Texas MD Anderson Cancer Center, Houston, Texas, USA
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161
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Telomere Damage Response and Low-Grade Inflammation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1024:213-224. [PMID: 28921472 DOI: 10.1007/978-981-10-5987-2_10] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Telomeres at the ends of chromosomes safeguard genome integrity and stability in human nucleated cells. However, telomere repeats shed off during cell proliferation and other stress responses. Our recent studies show that telomere attrition induces not only epithelial stem cell senescence but also low-grade inflammation in the lungs. The senescence-associated low-grade inflammation (SALI) is characteristic of alveolar stem cell replicative senescence, increased proinflammatory and anti-inflammatory cytokines, infiltrated immune cells, and spillover effects. To date, the mechanisms underlying SALI remain unclear. Investigations demonstrate that senescent epithelial stem cells with telomere erosion are not the source of secreted cytokines, containing no significant increase in expression of the genes coding for increased cytokines, suggesting an alternative senescence-associated secretory phenotype (A-SASP). Given that telomere loss results in significant alterations in the genomes and accumulations of the cleaved telomeric DNA in the cells and milieu externe, we conclude that telomere position effects (TPEs) on gene expression and damage-associated molecular patterns (DAMPs) in antigen presentation are involved in A-SASP and SALI in response to telomere damage in mammals.
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162
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Telomere-associated aging disorders. Ageing Res Rev 2017; 33:52-66. [PMID: 27215853 PMCID: PMC9926533 DOI: 10.1016/j.arr.2016.05.009] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 05/17/2016] [Accepted: 05/19/2016] [Indexed: 01/25/2023]
Abstract
Telomeres are dynamic nucleoprotein-DNA structures that cap and protect linear chromosome ends. Several monogenic inherited diseases that display features of human premature aging correlate with shortened telomeres, and are referred to collectively as telomeropathies. These disorders have overlapping symptoms and a common underlying mechanism of telomere dysfunction, but also exhibit variable symptoms and age of onset, suggesting they fall along a spectrum of disorders. Primary telomeropathies are caused by defects in the telomere maintenance machinery, whereas secondary telomeropathies have some overlapping symptoms with primary telomeropathies, but are generally caused by mutations in DNA repair proteins that contribute to telomere preservation. Here we review both the primary and secondary telomeropathies, discuss potential mechanisms for tissue specificity and age of onset, and highlight outstanding questions in the field and future directions toward elucidating disease etiology and developing therapeutic strategies.
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163
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Libertini G, Ferrara N. Possible interventions to modify aging. BIOCHEMISTRY (MOSCOW) 2016; 81:1413-1428. [DOI: 10.1134/s0006297916120038] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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164
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Kim W, Ludlow AT, Min J, Robin JD, Stadler G, Mender I, Lai TP, Zhang N, Wright WE, Shay JW. Regulation of the Human Telomerase Gene TERT by Telomere Position Effect-Over Long Distances (TPE-OLD): Implications for Aging and Cancer. PLoS Biol 2016; 14:e2000016. [PMID: 27977688 PMCID: PMC5169358 DOI: 10.1371/journal.pbio.2000016] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 11/10/2016] [Indexed: 02/07/2023] Open
Abstract
Telomerase is expressed in early human development and then becomes silenced in most normal tissues. Because ~90% of primary human tumors express telomerase and generally maintain very short telomeres, telomerase is carefully regulated, particularly in large, long-lived mammals. In the current report, we provide substantial evidence for a new regulatory control mechanism of the rate limiting catalytic protein component of telomerase (hTERT) that is determined by the length of telomeres. We document that normal, young human cells with long telomeres have a repressed hTERT epigenetic status (chromatin and DNA methylation), but the epigenetic status is altered when telomeres become short. The change in epigenetic status correlates with altered expression of TERT and genes near to TERT, indicating a change in chromatin. Furthermore, we identified a chromosome 5p telomere loop to a region near TERT in human cells with long telomeres that is disengaged with increased cell divisions as telomeres progressively shorten. Finally, we provide support for a role of the TRF2 protein, and possibly TERRA, in the telomere looping maintenance mechanism through interactions with interstitial TTAGGG repeats. This provides new insights into how the changes in genome structure during replicative aging result in an increased susceptibility to age-related diseases and cancer prior to the initiation of a DNA damage signal.
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Affiliation(s)
- Wanil Kim
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Andrew T Ludlow
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Jaewon Min
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Jerome D Robin
- Faculté de Médecine, Tour Pasteur 8éme Étage, Nice, France
| | - Guido Stadler
- Berkeley Lights, Inc., Emeryville, California, United States of America
| | - Ilgen Mender
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Tsung-Po Lai
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Ning Zhang
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Woodring E Wright
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Jerry W Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
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165
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Beerman I. Accumulation of DNA damage in the aged hematopoietic stem cell compartment. Semin Hematol 2016; 54:12-18. [PMID: 28088982 DOI: 10.1053/j.seminhematol.2016.11.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 11/10/2016] [Indexed: 02/07/2023]
Abstract
Aging is associated with loss of functional potential of multiple tissue systems, and there has been significant interest in understanding how tissue-specific cells contribute to this decline. DNA damage accumulation has been widely associated with aging in differentiated cell types. However, tissue-specific stem cells were once thought to be a geno-protected population, as damage accrued in a stem cell population has the potential to be inherited by differentiated progeny, as well as propagated within the stem cell compartment through self-renewal divisions. This review will discuss the evidence for DNA damage accumulation in the aged HSC compartment, potential drivers, and finally the consequences of the acquired damage.
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Affiliation(s)
- Isabel Beerman
- Translational Gerontology Branch, National Institute on Aging, NIH, Baltimore, MD.
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166
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Di Stefano M, Paulsen J, Lien TG, Hovig E, Micheletti C. Hi-C-constrained physical models of human chromosomes recover functionally-related properties of genome organization. Sci Rep 2016; 6:35985. [PMID: 27786255 PMCID: PMC5081523 DOI: 10.1038/srep35985] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 09/30/2016] [Indexed: 11/10/2022] Open
Abstract
Combining genome-wide structural models with phenomenological data is at the forefront of efforts to understand the organizational principles regulating the human genome. Here, we use chromosome-chromosome contact data as knowledge-based constraints for large-scale three-dimensional models of the human diploid genome. The resulting models remain minimally entangled and acquire several functional features that are observed in vivo and that were never used as input for the model. We find, for instance, that gene-rich, active regions are drawn towards the nuclear center, while gene poor and lamina associated domains are pushed to the periphery. These and other properties persist upon adding local contact constraints, suggesting their compatibility with non-local constraints for the genome organization. The results show that suitable combinations of data analysis and physical modelling can expose the unexpectedly rich functionally-related properties implicit in chromosome-chromosome contact data. Specific directions are suggested for further developments based on combining experimental data analysis and genomic structural modelling.
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Affiliation(s)
- Marco Di Stefano
- SISSA, International School for Advanced Studies, Trieste, I-34136, Italy
| | - Jonas Paulsen
- Institute of Basic Medical Sciences, University of Oslo, Oslo, 0317, Norway
| | - Tonje G. Lien
- University of Oslo, Department of Mathematics, Oslo, 0316, Norway
| | - Eivind Hovig
- Institute for Cancer Research, Oslo University Hospital, Department of Tumor Biology, Oslo, 0310, Norway
- University of Oslo, Department of Informatics, Oslo, 0316, Norway
- Institute of Cancer Genetics and Informatics, Oslo, 0310, Norway
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167
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Criscione SW, Teo YV, Neretti N. The Chromatin Landscape of Cellular Senescence. Trends Genet 2016; 32:751-761. [PMID: 27692431 DOI: 10.1016/j.tig.2016.09.005] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 09/12/2016] [Accepted: 09/13/2016] [Indexed: 12/20/2022]
Abstract
Cellular senescence, an irreversible growth arrest triggered by a variety of stressors, plays important roles in normal physiology and tumor suppression, but accumulation of senescent cells with age contributes to the functional decline of tissues. Senescent cells undergo dramatic alterations to their chromatin landscape that affect genome accessibility and their transcriptional program. These include the loss of DNA-nuclear lamina interactions, the distension of centromeres, and changes in chromatin composition that can lead to the activation of retrotransposons. Here we discuss these findings, as well as recent advances in microscopy and genomics that have revealed the importance of the higher-order spatial organization of the genome in defining and maintaining the senescent state.
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Affiliation(s)
- Steven W Criscione
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912, USA
| | - Yee Voan Teo
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912, USA
| | - Nicola Neretti
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912, USA; Center for Computational Molecular Biology, Brown University, Providence, RI 02912, USA.
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168
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Su X, Yao X, Sun Z, Han Q, Zhao RC. Optimization of Reference Genes for Normalization of Reverse Transcription Quantitative Real-Time Polymerase Chain Reaction Results in Senescence Study of Mesenchymal Stem Cells. Stem Cells Dev 2016; 25:1355-65. [PMID: 27484587 DOI: 10.1089/scd.2016.0031] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Recently, it has been suggested that cellular senescence is associated with stem cell exhaustion, which reduces the regenerative potential of tissues and contributes to aging and age-related diseases. Mesenchymal stem cells (MSCs) attract a large amount of attention in stem cell research and regeneration medicine because they possess multiple advantages and senescent MSCs could be one of the most useful stem cell models in aging studies. It is important to quantitatively evaluate senescence markers to both identify and study the mechanisms involved in MSC senescence. Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) is currently the most widely used tool to quantify the mRNA levels of markers. However, no report has demonstrated the optimal reference genes that should be used to normalize RT-qPCR in senescence studies of MSCs. In this study, we compared 16 commonly used reference genes (GAPDH, ACTB, RPL13A, TBP, B2M, GUSB, RPLPO, YWHAZ, RPS18, EEF1A1, ATP5F1, HPRT1, PGK1, TFRC, UBC, and PPIA) in proliferating or replicative-senescent human adipose-derived MSCs (hAD-MSCs) that were isolated from seven healthy donors aged 29-59 years old. Three algorithms (geNorm, NormFinder, and BestKeeper) were used to determine the most optimal reference gene. The results showed that PPIA exhibited the most stable expression during senescence, while the widely used ACTB exhibited the lowest stability. We also confirmed that different reference genes lead to different evaluations of senescence markers. Our work ensures that results obtained from senescence studies of hAD-MSCs will be appropriately evaluated in both basic research and clinical trials.
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Affiliation(s)
- Xiaodong Su
- 1 Institute of Basic Medical Sciences, School of Basic Medicine, Peking Union Medical College, Center of Excellence in Tissue Engineering, Chinese Academy of Medical Sciences , Beijing, People's Republic of China
| | - Xinglei Yao
- 1 Institute of Basic Medical Sciences, School of Basic Medicine, Peking Union Medical College, Center of Excellence in Tissue Engineering, Chinese Academy of Medical Sciences , Beijing, People's Republic of China .,2 State Key Laboratory of Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing, People's Republic of China
| | - Zhao Sun
- 3 Department of Oncology, School of Basic Medicine, Peking Union Medical College, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences , Beijing, People's Republic of China
| | - Qin Han
- 1 Institute of Basic Medical Sciences, School of Basic Medicine, Peking Union Medical College, Center of Excellence in Tissue Engineering, Chinese Academy of Medical Sciences , Beijing, People's Republic of China
| | - Robert Chunhua Zhao
- 1 Institute of Basic Medical Sciences, School of Basic Medicine, Peking Union Medical College, Center of Excellence in Tissue Engineering, Chinese Academy of Medical Sciences , Beijing, People's Republic of China
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169
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Robin JD, Magdinier F. Physiological and Pathological Aging Affects Chromatin Dynamics, Structure and Function at the Nuclear Edge. Front Genet 2016; 7:153. [PMID: 27602048 PMCID: PMC4993774 DOI: 10.3389/fgene.2016.00153] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 08/08/2016] [Indexed: 01/29/2023] Open
Abstract
Lamins are intermediate filaments that form a complex meshwork at the inner nuclear membrane. Mammalian cells express two types of Lamins, Lamins A/C and Lamins B, encoded by three different genes, LMNA, LMNB1, and LMNB2. Mutations in the LMNA gene are associated with a group of phenotypically diverse diseases referred to as laminopathies. Lamins interact with a large number of binding partners including proteins of the nuclear envelope but also chromatin-associated factors. Lamins not only constitute a scaffold for nuclear shape, rigidity and resistance to stress but also contribute to the organization of chromatin and chromosomal domains. We will discuss here the impact of A-type Lamins loss on alterations of chromatin organization and formation of chromatin domains and how disorganization of the lamina contributes to the patho-physiology of premature aging syndromes.
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Affiliation(s)
- Jérôme D Robin
- IRCAN, CNRS UMR 7284/INSERM U1081, Faculté de Médecine Nice, France
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170
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Wood WA, Krishnamurthy J, Mitin N, Torrice C, Parker JS, Snavely AC, Shea TC, Serody JS, Sharpless NE. Chemotherapy and Stem Cell Transplantation Increase p16 INK4a Expression, a Biomarker of T-cell Aging. EBioMedicine 2016; 11:227-238. [PMID: 27591832 PMCID: PMC5049997 DOI: 10.1016/j.ebiom.2016.08.029] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 08/16/2016] [Accepted: 08/19/2016] [Indexed: 12/13/2022] Open
Abstract
The expression of markers of cellular senescence increases exponentially in multiple tissues with aging. Age-related physiological changes may contribute to adverse outcomes in cancer survivors. To investigate the impact of high dose chemotherapy and stem cell transplantation on senescence markers in vivo, we collected blood and clinical data from a cohort of 63 patients undergoing hematopoietic cell transplantation. The expression of p16INK4a, a well-established senescence marker, was determined in T-cells before and 6 months after transplant. RNA sequencing was performed on paired samples from 8 patients pre- and post-cancer therapy. In patients undergoing allogeneic transplant, higher pre-transplant p16INK4a expression was associated with a greater number of prior cycles of chemotherapy received (p = 0.003), prior autologous transplantation (p = 0.01) and prior exposure to alkylating agents (p = 0.01). Transplantation was associated with a marked increase in p16INK4a expression 6 months following transplantation. Patients receiving autologous transplant experienced a larger increase in p16INK4a expression (3.1-fold increase, p = 0.002) than allogeneic transplant recipients (1.9-fold increase, p = 0.0004). RNA sequencing of T-cells pre- and post- autologous transplant or cytotoxic chemotherapy demonstrated increased expression of transcripts associated with cellular senescence and physiological aging. Cytotoxic chemotherapy, especially alkylating agents, and stem cell transplantation strongly accelerate expression of a biomarker of molecular aging in T-cells. Peripheral blood T-cell senescence, as measured by the marker p16INK4a, increases following autologous or allogeneic HSCT. RNAseq of T-cells post- auto HSCT or chemotherapy show increased expression of transcripts associated with senescence. Autologous HCT in particular induces a stronger effect on Tcell p16INK4a expression than any other environmental stimulus tested to date.
Human chronological aging is associated with increased expression of markers of cellular aging (senescence). Cancer chemotherapy can produce frailty syndromes – recipients of cancer treatment may experience physiological changes ordinarily seen in individuals of more advanced chronological age. In our study, we found that a well-known marker of cellular senescence, p16INK4a, increased in patients following autologous or allogeneic hematopoietic cell transplantation. Expression of p16INK4a was higher in patients exposed to greater amounts of chemotherapy before transplant and those exposed to specific types of chemotherapy. These findings may ultimately influence clinical decision-making for patients with diseases that are commonly treated with transplantation.
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Affiliation(s)
- William A Wood
- Department of Medicine, The Lineberger Comprehensive Cancer Center, The University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Janakiraman Krishnamurthy
- Department of Medicine, The Lineberger Comprehensive Cancer Center, The University of North Carolina School of Medicine, Chapel Hill, NC, USA; Department of Genetics, The Lineberger Comprehensive Cancer Center, The University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Natalia Mitin
- Department of Medicine, The Lineberger Comprehensive Cancer Center, The University of North Carolina School of Medicine, Chapel Hill, NC, USA; Department of Genetics, The Lineberger Comprehensive Cancer Center, The University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Chad Torrice
- Department of Medicine, The Lineberger Comprehensive Cancer Center, The University of North Carolina School of Medicine, Chapel Hill, NC, USA; Department of Genetics, The Lineberger Comprehensive Cancer Center, The University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Joel S Parker
- Department of Genetics, The Lineberger Comprehensive Cancer Center, The University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Anna C Snavely
- Department of Medicine, The Lineberger Comprehensive Cancer Center, The University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Thomas C Shea
- Department of Medicine, The Lineberger Comprehensive Cancer Center, The University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Jonathan S Serody
- Department of Medicine, The Lineberger Comprehensive Cancer Center, The University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Norman E Sharpless
- Department of Medicine, The Lineberger Comprehensive Cancer Center, The University of North Carolina School of Medicine, Chapel Hill, NC, USA; Department of Genetics, The Lineberger Comprehensive Cancer Center, The University of North Carolina School of Medicine, Chapel Hill, NC, USA.
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171
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Telomere Transcripts Target Telomerase in Human Cancer Cells. Genes (Basel) 2016; 7:genes7080046. [PMID: 27537914 PMCID: PMC4999834 DOI: 10.3390/genes7080046] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 07/24/2016] [Accepted: 07/29/2016] [Indexed: 12/14/2022] Open
Abstract
Long non-coding transcripts from telomeres, called telomeric repeat-containing RNA (TERRA), were identified as blocking telomerase activity (TA), a telomere maintenance mechanism (TMM), in tumors. We expressed recombinant TERRA transcripts in tumor cell lines with TA and with alternative lengthening of telomeres (ALT) to study effects on TMM and cell growth. Adeno- and lentivirus constructs (AV and LV) were established for transient and stable expression of approximately 130 units of telomere hexanucleotide repeats under control of cytomegalovirus (CMV) and human RNase P RNA H1 (hH1) promoters with and without polyadenylation, respectively. Six human tumor cell lines either using telomerase or ALT were infected and analyzed for TA levels. Pre-infection cells using telomerase had 1%-3% of the TERRA expression levels of ALT cells. AV and LV expression of recombinant TERRA in telomerase positive cells showed a 1.3-2.6 fold increase in TERRA levels, and a decrease in TA of 25%-58%. Dominant-negative or small hairpin RNA (shRNA) viral expression against human telomerase reverse transcriptase (hTERT) results in senescence, not induced by TERRA expression. Population doubling time, cell viability and TL (telomere length) were not impacted by ectopic TERRA expression. Clonal growth was reduced by TERRA expression in TA but not ALT cell lines. ALT cells were not affected by treatments applied. Established cell models and tools may be used to better understand the role of TERRA in the cell, especially for targeting telomerase.
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172
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Abstract
Telomeres maintain genomic integrity in normal cells, and their progressive shortening during successive cell divisions induces chromosomal instability. In the large majority of cancer cells, telomere length is maintained by telomerase. Thus, telomere length and telomerase activity are crucial for cancer initiation and the survival of tumors. Several pathways that regulate telomere length have been identified, and genome-scale studies have helped in mapping genes that are involved in telomere length control. Additionally, genomic screening for recurrent human telomerase gene hTERT promoter mutations and mutations in genes involved in the alternative lengthening of telomeres pathway, such as ATRX and DAXX, has elucidated how these genomic changes contribute to the activation of telomere maintenance mechanisms in cancer cells. Attempts have also been made to develop telomere length- and telomerase-based diagnostic tools and anticancer therapeutics. Recent efforts have revealed key aspects of telomerase assembly, intracellular trafficking and recruitment to telomeres for completing DNA synthesis, which may provide novel targets for the development of anticancer agents. Here, we summarize telomere organization and function and its role in oncogenesis. We also highlight genomic mutations that lead to reactivation of telomerase, and mechanisms of telomerase reconstitution and trafficking that shed light on its function in cancer initiation and tumor development. Additionally, recent advances in the clinical development of telomerase inhibitors, as well as potential novel targets, will be summarized.
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173
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Nersisyan L. Integration of Telomere Length Dynamics into Systems Biology Framework: A Review. GENE REGULATION AND SYSTEMS BIOLOGY 2016; 10:35-42. [PMID: 27346946 PMCID: PMC4912229 DOI: 10.4137/grsb.s39836] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 05/11/2016] [Accepted: 05/21/2016] [Indexed: 01/02/2023]
Abstract
Telomere length dynamics plays a crucial role in regulation of cellular processes and cell fate. In contrast to epidemiological studies revealing the association of telomere length with age, age-related diseases, and cancers, the role of telomeres in regulation of transcriptome and epigenome and the role of genomic variations in telomere lengthening are not extensively analyzed. This is explained by the fact that experimental assays for telomere length measurement are resource consuming, and there are very few studies where high-throughput genomics, transcriptomics, and/or epigenomics experiments have been coupled with telomere length measurements. Recent development of computational approaches for assessment of telomere length from whole genome sequencing data pave a new perspective on integration of telomeres into high-throughput systems biology analysis framework. Herein, we review existing methodologies for telomere length measurement and compare them to computational approaches, as well as discuss their applications in large-scale studies on telomere length dynamics.
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Affiliation(s)
- Lilit Nersisyan
- Group of Bioinformatics, Institute of Molecular Biology, National Academy of Sciences RA, Yerevan, Republic of Armenia
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174
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Abstract
UNLABELLED Telomeres progressively shorten throughout life. A hallmark of advanced malignancies is the ability for continuous cell divisions that almost universally correlates with the stabilization of telomere length by the reactivation of telomerase. The repression of telomerase and shorter telomeres in humans may have evolved, in part, as an anticancer protection mechanism. Although there is still much we do not understand about the regulation of telomerase, it remains a very attractive and novel target for cancer therapeutics. This review focuses on the current state of advances in the telomerase area, identifies outstanding questions, and addresses areas and methods that need refinement. SIGNIFICANCE Despite many recent advances, telomerase remains a challenging target for cancer therapy. There are few telomerase-directed therapies, and many of the assays used to measure telomeres and telomerase have serious limitations. This review provides an overview of the current state of the field and how recent advances could affect future research and treatment approaches. Cancer Discov; 6(6); 584-93. ©2016 AACR.
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Affiliation(s)
- Jerry W Shay
- Department of Cell Biology, The University of Texas Southwestern Medical Center, Dallas, Texas. Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia.
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175
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Wood AM, Laster K, Rice EL, Kosak ST. A beginning of the end: new insights into the functional organization of telomeres. Nucleus 2016; 6:172-8. [PMID: 25961132 PMCID: PMC4615733 DOI: 10.1080/19491034.2015.1048407] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Ever since the first demonstration of their repetitive sequence and unique replication pathway, telomeres have beguiled researchers with how they function in protecting chromosome ends. Of course much has been learned over the years, and we now appreciate that telomeres are comprised of the multimeric protein/DNA shelterin complex and that the formation of t-loops provides protection from DNA damage machinery. Deriving their name from D-loops, t-loops are generated by the insertion of the 3′ overhang into telomeric repeats facilitated by the binding of TRF2. Recent studies have uncovered novel forms of chromosome end-structure that may implicate telomere organization in cellular processes beyond its essential role in telomere protection and homeostasis. In particular, we have recently described that t-loops form in a TRF2-dependent manner at interstitial telomere repeat sequences, which we termed interstitial telomere loops (ITLs). These structures are also dependent on association of lamin A/C, a canonical component of the nucleoskeleton that is mutated in myriad human diseases, including human segmental progeroid syndromes. Since ITLs are associated with telomere stability and require functional lamin A/C, our study suggests a mechanistic link between cellular aging (replicative senescence induced by telomere shortening) and organismal aging (modeled by Hutchinson Gilford Progeria Syndrome). Here we speculate on other potential ramifications of ITL formation, from gene expression to genome stability to chromosome structure.
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Affiliation(s)
- Ashley M Wood
- a Department of Cell and Molecular Biology; Feinberg School of Medicine; Northwestern University ; Chicago , IL , USA
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176
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Comparison of DNA Quantification Methods for Next Generation Sequencing. Sci Rep 2016; 6:24067. [PMID: 27048884 PMCID: PMC4822169 DOI: 10.1038/srep24067] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 03/21/2016] [Indexed: 12/18/2022] Open
Abstract
Next Generation Sequencing (NGS) is a powerful tool that depends on loading a precise amount of DNA onto a flowcell. NGS strategies have expanded our ability to investigate genomic phenomena by referencing mutations in cancer and diseases through large-scale genotyping, developing methods to map rare chromatin interactions (4C; 5C and Hi-C) and identifying chromatin features associated with regulatory elements (ChIP-seq, Bis-Seq, ChiA-PET). While many methods are available for DNA library quantification, there is no unambiguous gold standard. Most techniques use PCR to amplify DNA libraries to obtain sufficient quantities for optical density measurement. However, increased PCR cycles can distort the library’s heterogeneity and prevent the detection of rare variants. In this analysis, we compared new digital PCR technologies (droplet digital PCR; ddPCR, ddPCR-Tail) with standard methods for the titration of NGS libraries. DdPCR-Tail is comparable to qPCR and fluorometry (QuBit) and allows sensitive quantification by analysis of barcode repartition after sequencing of multiplexed samples. This study provides a direct comparison between quantification methods throughout a complete sequencing experiment and provides the impetus to use ddPCR-based quantification for improvement of NGS quality.
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177
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Silva S, Altmannova V, Luke-Glaser S, Henriksen P, Gallina I, Yang X, Choudhary C, Luke B, Krejci L, Lisby M. Mte1 interacts with Mph1 and promotes crossover recombination and telomere maintenance. Genes Dev 2016; 30:700-17. [PMID: 26966248 PMCID: PMC4803055 DOI: 10.1101/gad.276204.115] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 02/17/2016] [Indexed: 11/25/2022]
Abstract
Mph1 is a member of the conserved FANCM family of DNA motor proteins that play key roles in genome maintenance processes underlying Fanconi anemia, a cancer predisposition syndrome in humans. Here, we identify Mte1 as a novel interactor of the Mph1 helicase in Saccharomyces cerevisiae. In vitro, Mte1 (Mph1-associated telomere maintenance protein 1) binds directly to DNA with a preference for branched molecules such as D loops and fork structures. In addition, Mte1 stimulates the helicase and fork regression activities of Mph1 while inhibiting the ability of Mph1 to dissociate recombination intermediates. Deletion of MTE1 reduces crossover recombination and suppresses the sensitivity of mph1Δ mutant cells to replication stress. Mph1 and Mte1 interdependently colocalize at DNA damage-induced foci and dysfunctional telomeres, and MTE1 deletion results in elongated telomeres. Taken together, our data indicate that Mte1 plays a role in regulation of crossover recombination, response to replication stress, and telomere maintenance.
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Affiliation(s)
- Sonia Silva
- Department of Biology, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | | | | | - Peter Henriksen
- The Novo Nordisk Foundation Center for Protein Research, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Irene Gallina
- Department of Biology, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Xuejiao Yang
- Department of Biology, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Chunaram Choudhary
- The Novo Nordisk Foundation Center for Protein Research, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Brian Luke
- Institute of Molecular Biology gGmbH (IMB), 55128 Mainz, Germany
| | - Lumir Krejci
- Department of Biology, Masaryk University, CZ-62500 Brno, Czech Republic; National Centre for Biomolecular Research, Masaryk University, CZ-62500 Brno, Czech Republic; International Clinical Research Center, St. Anne's University Hospital Brno, CZ-656 91 Brno, Czech Republic; Center for Biomolecular and Cellular Engineering, St. Anne's University Hospital Brno, CZ-656 91 Brno, Czech Republic
| | - Michael Lisby
- Department of Biology, University of Copenhagen, DK-2200 Copenhagen N, Denmark; Center for Chromosome Stability, Department of Cellular and Molecular Medicine, University of Copenhagen, DK-2200 Copenhagen N, Denmark
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178
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Zhang E, Cotton VE, Hidalgo-Bravo A, Huang Y, Bell AJ, Jarrett RF, Wilkie GS, Davison AJ, Nacheva EP, Siebert R, Majid A, Kelpanides I, Jayne S, Dyer MJ, Royle NJ. HHV-8-unrelated primary effusion-like lymphoma associated with clonal loss of inherited chromosomally-integrated human herpesvirus-6A from the telomere of chromosome 19q. Sci Rep 2016; 6:22730. [PMID: 26947392 PMCID: PMC4779988 DOI: 10.1038/srep22730] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Accepted: 02/18/2016] [Indexed: 12/26/2022] Open
Abstract
Primary effusion lymphomas (PEL) are associated with human herpesvirus-8 (HHV-8) and usually occur in immunocompromised individuals. However, there are numerous reports of HHV-8-unrelated PEL-like lymphomas with unknown aetiology. Here we characterize an HHV-8-unrelated PEL-like lymphoma in an elderly woman who was negative for human immunodeficiency viruses 1 and 2, and hepatitis B and C. The woman was, however, a carrier of an inherited-chromosomally-integrated human herpesvirus-6A (iciHHV-6A) genome in one 19q telomere. The iciHHV-6A genome was complete in blood DNA, encoding a full set of protein-coding genes. Interestingly, the entire iciHHV-6A genome was absent from the HHV-8-unrelated-PEL-like lymphoma cells despite retention of both copies of chromosome 19. The somatic loss of the 19q-iciHHV-6A genome occurred very early during lymphoma development and we propose it occurred via telomere-loop formation and excision to release a circular viral genome that was subsequently lost. Whether release of the HHV-6A genome from the telomere contributed to lymphomagenesis, or was coincidental, remains unclear but this event may have deregulated the expression of HHV-6A or 19q genes or else disrupted telomere function. To establish the frequency and importance of iciHHV-6 loss from telomeres, the HHV-6 copy number should be assessed in tumours that arise in iciHHV-6 carriers.
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Affiliation(s)
- Enjie Zhang
- Department of Genetics, University of Leicester, Leicester, LE1 7RH, UK
| | - Victoria E Cotton
- Department of Genetics, University of Leicester, Leicester, LE1 7RH, UK
| | | | - Yan Huang
- Department of Genetics, University of Leicester, Leicester, LE1 7RH, UK
| | - Adam J Bell
- MRC - University of Glasgow Centre for Virus Research, Glasgow G61 1QH, UK
| | - Ruth F Jarrett
- MRC - University of Glasgow Centre for Virus Research, Glasgow G61 1QH, UK
| | - Gavin S Wilkie
- MRC - University of Glasgow Centre for Virus Research, Glasgow G61 1QH, UK
| | - Andrew J Davison
- MRC - University of Glasgow Centre for Virus Research, Glasgow G61 1QH, UK
| | - Ellie P Nacheva
- Cytogenetics Laboratory, Royal Free London NHS Foundation Trust, London, NW3 2PF, UK
| | - Reiner Siebert
- Institute of Human Genetics, Christian-Albrechts-University Kiel &University Hospital Schleswig-Holstein, Campus Kiel, Schwanenweg 24, D-24105 Kiel, Germany
| | - Aneela Majid
- Ernest and Helen Scott Haematological Research Institute, Department of Cancer Studies, University of Leicester, Leicester, LE1 7RH, UK
| | - Inga Kelpanides
- Ernest and Helen Scott Haematological Research Institute, Department of Cancer Studies, University of Leicester, Leicester, LE1 7RH, UK
| | - Sandrine Jayne
- Ernest and Helen Scott Haematological Research Institute, Department of Cancer Studies, University of Leicester, Leicester, LE1 7RH, UK
| | - Martin J Dyer
- Ernest and Helen Scott Haematological Research Institute, Department of Cancer Studies, University of Leicester, Leicester, LE1 7RH, UK
| | - Nicola J Royle
- Department of Genetics, University of Leicester, Leicester, LE1 7RH, UK
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179
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TERRA and the state of the telomere. Nat Struct Mol Biol 2016; 22:853-8. [PMID: 26581519 DOI: 10.1038/nsmb.3078] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 07/29/2015] [Indexed: 02/05/2023]
Abstract
Long noncoding telomeric repeat-containing RNA (TERRA) has been implicated in telomere maintenance in a telomerase-dependent and a telomerase-independent manner during replicative senescence and cancer. TERRA's proposed activities are diverse, thus making it difficult to pinpoint the critical roles that TERRA may have. We propose that TERRA orchestrates different activities at chromosome ends in a manner that depends on the state of the telomere.
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180
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Hehar H, Mychasiuk R. The use of telomere length as a predictive biomarker for injury prognosis in juvenile rats following a concussion/mild traumatic brain injury. Neurobiol Dis 2016; 87:11-8. [DOI: 10.1016/j.nbd.2015.12.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 11/23/2015] [Accepted: 12/14/2015] [Indexed: 02/04/2023] Open
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181
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Telomere Length Maintenance and Cardio-Metabolic Disease Prevention Through Exercise Training. Sports Med 2016; 46:1213-37. [DOI: 10.1007/s40279-016-0482-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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182
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183
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Zhang J, Rane G, Dai X, Shanmugam MK, Arfuso F, Samy RP, Lai MKP, Kappei D, Kumar AP, Sethi G. Ageing and the telomere connection: An intimate relationship with inflammation. Ageing Res Rev 2016; 25:55-69. [PMID: 26616852 DOI: 10.1016/j.arr.2015.11.006] [Citation(s) in RCA: 251] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 11/16/2015] [Accepted: 11/19/2015] [Indexed: 12/19/2022]
Abstract
Telomeres are the heterochromatic repeat regions at the ends of eukaryotic chromosomes, whose length is considered to be a determinant of biological ageing. Normal ageing itself is associated with telomere shortening. Here, critically short telomeres trigger senescence and eventually cell death. This shortening rate may be further increased by inflammation and oxidative stress and thus affect the ageing process. Apart from shortened or dysfunctional telomeres, cells undergoing senescence are also associated with hyperactivity of the transcription factor NF-κB and overexpression of inflammatory cytokines such as TNF-α, IL-6, and IFN-γ in circulating macrophages. Interestingly, telomerase, a reverse transcriptase that elongates telomeres, is involved in modulating NF-κB activity. Furthermore, inflammation and oxidative stress are implicated as pre-disease mechanisms for chronic diseases of ageing such as neurodegenerative diseases, cardiovascular disease, and cancer. To date, inflammation and telomere shortening have mostly been studied individually in terms of ageing and the associated disease phenotype. However, the interdependent nature of the two demands a more synergistic approach in understanding the ageing process itself and for developing new therapeutic approaches. In this review, we aim to summarize the intricate association between the various inflammatory molecules and telomeres that together contribute to the ageing process and related diseases.
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184
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Wylie A, Jones AE, D'Brot A, Lu WJ, Kurtz P, Moran JV, Rakheja D, Chen KS, Hammer RE, Comerford SA, Amatruda JF, Abrams JM. p53 genes function to restrain mobile elements. Genes Dev 2015; 30:64-77. [PMID: 26701264 PMCID: PMC4701979 DOI: 10.1101/gad.266098.115] [Citation(s) in RCA: 134] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 11/23/2015] [Indexed: 11/24/2022]
Abstract
Wylie et al. show that p53 restricts retrotransposon activity and genetically interacts with components of the piRNA pathway. In gene complementation studies, normal human p53 alleles restrained these mobile elements, but mutant p53 alleles from cancer patients could not. Consistent with these observations, they also found patterns of unrestrained retrotransposons in p53-driven mouse and human cancers. Throughout the animal kingdom, p53 genes govern stress response networks by specifying adaptive transcriptional responses. The human member of this gene family is mutated in most cancers, but precisely how p53 functions to mediate tumor suppression is not well understood. Using Drosophila and zebrafish models, we show that p53 restricts retrotransposon activity and genetically interacts with components of the piRNA (piwi-interacting RNA) pathway. Furthermore, transposon eruptions occurring in the p53− germline were incited by meiotic recombination, and transcripts produced from these mobile elements accumulated in the germ plasm. In gene complementation studies, normal human p53 alleles suppressed transposons, but mutant p53 alleles from cancer patients could not. Consistent with these observations, we also found patterns of unrestrained retrotransposons in p53-driven mouse and human cancers. Furthermore, p53 status correlated with repressive chromatin marks in the 5′ sequence of a synthetic LINE-1 element. Together, these observations indicate that ancestral functions of p53 operate through conserved mechanisms to contain retrotransposons. Since human p53 mutants are disabled for this activity, our findings raise the possibility that p53 mitigates oncogenic disease in part by restricting transposon mobility.
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Affiliation(s)
- Annika Wylie
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Amanda E Jones
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Alejandro D'Brot
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Wan-Jin Lu
- Stanford University Medical Center, Stanford, California 94305, USA
| | - Paula Kurtz
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - John V Moran
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan 48019, USA; Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48019, USA; Howard Hughes Medical Institute, University of Michigan Medical School, Ann Arbor, Michigan 48019, USA
| | - Dinesh Rakheja
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA; Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Kenneth S Chen
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Robert E Hammer
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Sarah A Comerford
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - James F Amatruda
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA; Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - John M Abrams
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
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185
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Tutton S, Azzam GA, Stong N, Vladimirova O, Wiedmer A, Monteith JA, Beishline K, Wang Z, Deng Z, Riethman H, McMahon SB, Murphy M, Lieberman PM. Subtelomeric p53 binding prevents accumulation of DNA damage at human telomeres. EMBO J 2015; 35:193-207. [PMID: 26658110 DOI: 10.15252/embj.201490880] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 11/11/2015] [Indexed: 11/09/2022] Open
Abstract
Telomeres and tumor suppressor protein TP53 (p53) function in genome protection, but a direct role of p53 at telomeres has not yet been described. Here, we have identified non-canonical p53-binding sites within the human subtelomeres that suppress the accumulation of DNA damage at telomeric repeat DNA. These non-canonical subtelomeric p53-binding sites conferred transcription enhancer-like functions that include an increase in local histone H3K9 and H3K27 acetylation and stimulation of subtelomeric transcripts, including telomere repeat-containing RNA (TERRA). p53 suppressed formation of telomere-associated γH2AX and prevented telomere DNA degradation in response to DNA damage stress. Our findings indicate that p53 provides a direct chromatin-associated protection to human telomeres, as well as other fragile genomic sites. We propose that p53-associated chromatin modifications enhance local DNA repair or protection to provide a previously unrecognized tumor suppressor function of p53.
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Affiliation(s)
| | | | | | | | | | - Jessica A Monteith
- Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | | | - Zhuo Wang
- The Wistar Institute, Philadelphia, PA, USA
| | - Zhong Deng
- The Wistar Institute, Philadelphia, PA, USA
| | | | - Steven B McMahon
- Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
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186
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Libertini G. Phylogeny of aging and related phenoptotic phenomena. BIOCHEMISTRY (MOSCOW) 2015; 80:1529-46. [DOI: 10.1134/s0006297915120019] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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187
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Robin JD, Ludlow AT, Batten K, Gaillard MC, Stadler G, Magdinier F, Wright WE, Shay JW. SORBS2 transcription is activated by telomere position effect-over long distance upon telomere shortening in muscle cells from patients with facioscapulohumeral dystrophy. Genome Res 2015; 25:1781-90. [PMID: 26359233 PMCID: PMC4665000 DOI: 10.1101/gr.190660.115] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 09/09/2015] [Indexed: 01/05/2023]
Abstract
DNA is organized into complex three-dimensional chromatin structures, but how this spatial organization regulates gene expression remains a central question. These DNA/chromatin looping structures can range in size from 10-20 kb (enhancers/repressors) to many megabases during intra- and inter-chromosomal interactions. Recently, the influence of telomere length on chromatin organization prior to senescence has revealed the existence of long-distance chromatin loops that dictate the expression of genes located up to 10 Mb from the telomeres (Telomere Position Effect-Over Long Distances [TPE-OLD]). Here, we demonstrate the existence of a telomere loop at the 4q35 locus involving the sorbin and SH3 domain-containing protein 2 gene, SORBS2, a skeletal muscle protein using a modification of the chromosome conformation capture method. The loop reveals a cis-acting mechanism modifying SORBS2 transcription. The expression of this gene is altered by TPE-OLD in myoblasts from patients affected with the age-associated genetic disease, facioscapulohumeral muscular dystrophy (FSHD1A, MIM 158900). SORBS2 is expressed in FSHD myoblasts with short telomeres, while not detectable in FSHD myoblasts with long telomeres or in healthy myoblasts regardless of telomere length. This indicates that TPE-OLD may modify the regulation of the 4q35 locus in a pathogenic context. Upon differentiation, both FSHD and healthy myotubes express SORBS2, suggesting that SORBS2 is normally up-regulated by maturation/differentiation of skeletal muscle and is misregulated by TPE-OLD-dependent variegation in FSHD myoblasts. These findings provide additional insights for the complexity and age-related symptoms of FSHD.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Biopsy
- Chromosome Deletion
- Chromosomes, Human, Pair 4
- DNA Methylation
- Epistasis, Genetic
- Gene Expression Regulation
- Genetic Loci
- Homeodomain Proteins/genetics
- Homeodomain Proteins/metabolism
- Humans
- In Situ Hybridization, Fluorescence
- Muscle Cells/metabolism
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Muscular Dystrophy, Facioscapulohumeral/genetics
- Muscular Dystrophy, Facioscapulohumeral/metabolism
- Muscular Dystrophy, Facioscapulohumeral/pathology
- MyoD Protein/genetics
- MyoD Protein/metabolism
- Myoblasts
- RNA-Binding Proteins
- Telomere/genetics
- Telomere Shortening
- Transcriptional Activation
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Affiliation(s)
- Jérôme D Robin
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Andrew T Ludlow
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Kimberly Batten
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas 75390, USA
| | | | - Guido Stadler
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas 75390, USA
| | | | - Woodring E Wright
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Jerry W Shay
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas 75390, USA; Center for Excellence in Genomics Medicine Research, King Abdulaziz University, Jeddah 21589, Saudi Arabia
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188
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Hohensinner PJ, Kaun C, Buchberger E, Ebenbauer B, Demyanets S, Huk I, Eppel W, Maurer G, Huber K, Wojta J. Age intrinsic loss of telomere protection via TRF1 reduction in endothelial cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:360-7. [PMID: 26658719 DOI: 10.1016/j.bbamcr.2015.11.034] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 11/26/2015] [Accepted: 11/28/2015] [Indexed: 12/30/2022]
Abstract
Aging is a major factor predisposing for multiple diseases. Telomeres at the ends of chromosomes protect the integrity of chromosomal DNA. A specialized six-protein complex termed shelterin protects the telomere from unwanted interaction with DNA damage pathways. The aim of our study was to evaluate the integrity of telomeres and the stability of telomere protection during aging in endothelial cells (EC). We describe that aging EC can be characterized by an increased cell size (40%, p=0.02) and increased expression of PAI 1 (4 fold, p=0.02), MCP1 (10 fold, p=0.001) and GMCSF (15 fold, p=0.004). Telomeric state in aging cells is defined by an increased telomere oxidation (27%, p=0.01), reduced telomere length (62%, p=0.02), and increased DNA damage foci formation (5% in young EC versus 16% in aged EC, p=0.003). This telomeric dysfunction is accompanied by a reduction in the shelterin component TRF1 (33% mRNA, p=0.001; 24% protein, p=0.007). Overexpression of TRF1 in aging EC reduced telomere-associated DNA damage foci to 5% (p=0.02) and reduced expression levels of MCP1 (18% reduction, p=0.008). Aged EC have increased telomere damage and an intrinsic loss of telomere protection. Reestablishing telomere integrity could therefore be a target for rejuvenating endothelial cell function.
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Affiliation(s)
- P J Hohensinner
- Department of Internal Medicine II, Cardiology, Medical University of Vienna, Vienna, Austria.
| | - C Kaun
- Department of Internal Medicine II, Cardiology, Medical University of Vienna, Vienna, Austria
| | - E Buchberger
- Department of Surgery, Medical University of Vienna, Vienna, Austria
| | - B Ebenbauer
- Department of Internal Medicine II, Cardiology, Medical University of Vienna, Vienna, Austria; Ludwig Boltzmann Cluster for Cardiovascular Research, Vienna, Austria
| | - S Demyanets
- Department of Internal Medicine II, Cardiology, Medical University of Vienna, Vienna, Austria; Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
| | - I Huk
- Department of Surgery, Division of Vascular Surgery, Medical University of Vienna, Vienna, Austria
| | - W Eppel
- Department of Gynecology, Medical University of Vienna, Vienna, Austria
| | - G Maurer
- Department of Internal Medicine II, Cardiology, Medical University of Vienna, Vienna, Austria
| | - K Huber
- Ludwig Boltzmann Cluster for Cardiovascular Research, Vienna, Austria; 3rd Medical Department, Wilhelminenhospital, Vienna, Austria
| | - J Wojta
- Department of Internal Medicine II, Cardiology, Medical University of Vienna, Vienna, Austria; Ludwig Boltzmann Cluster for Cardiovascular Research, Vienna, Austria; Core Facilities, Medical University of Vienna, Vienna, Austria
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189
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Chen R, Zhang K, Chen H, Zhao X, Wang J, Li L, Cong Y, Ju Z, Xu D, Williams BRG, Jia J, Liu JP. Telomerase Deficiency Causes Alveolar Stem Cell Senescence-associated Low-grade Inflammation in Lungs. J Biol Chem 2015; 290:30813-29. [PMID: 26518879 DOI: 10.1074/jbc.m115.681619] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Indexed: 12/16/2022] Open
Abstract
Mutations of human telomerase RNA component (TERC) and telomerase reverse transcriptase (TERT) are associated with a subset of lung aging diseases, but the mechanisms by which TERC and TERT participate in lung diseases remain unclear. In this report, we show that knock-out (KO) of the mouse gene Terc or Tert causes pulmonary alveolar stem cell replicative senescence, epithelial impairment, formation of alveolar sacs, and characteristic inflammatory phenotype. Deficiency in TERC or TERT causes a remarkable elevation in various proinflammatory cytokines, including IL-1, IL-6, CXCL15 (human IL-8 homolog), IL-10, TNF-α, and monocyte chemotactic protein 1 (chemokine ligand 2 (CCL2)); decrease in TGF-β1 and TGFβRI receptor in the lungs; and spillover of IL-6 and CXCL15 into the bronchoalveolar lavage fluids. In addition to increased gene expressions of α-smooth muscle actin and collagen 1α1, suggesting myofibroblast differentiation, TERC deficiency also leads to marked cellular infiltrations of a mononuclear cell population positive for the leukocyte common antigen CD45, low-affinity Fc receptor CD16/CD32, and pattern recognition receptor CD11b in the lungs. Our data demonstrate for the first time that telomerase deficiency triggers alveolar stem cell replicative senescence-associated low-grade inflammation, thereby driving pulmonary premature aging, alveolar sac formation, and fibrotic lesion.
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Affiliation(s)
- Ruping Chen
- From the Department of Microbiology/Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Medicine, Shandong University, Jinan, Shandong Province 250012, China, the Institute of Aging Research, Hangzhou Normal University, School of Medicine, Hangzhou, Zhejiang Province 311121, China
| | - Kexiong Zhang
- the Institute of Aging Research, Hangzhou Normal University, School of Medicine, Hangzhou, Zhejiang Province 311121, China
| | - Hao Chen
- the Institute of Aging Research, Hangzhou Normal University, School of Medicine, Hangzhou, Zhejiang Province 311121, China
| | - Xiaoyin Zhao
- the Institute of Aging Research, Hangzhou Normal University, School of Medicine, Hangzhou, Zhejiang Province 311121, China
| | - Jianqiu Wang
- the Institute of Aging Research, Hangzhou Normal University, School of Medicine, Hangzhou, Zhejiang Province 311121, China
| | - Li Li
- the Institute of Aging Research, Hangzhou Normal University, School of Medicine, Hangzhou, Zhejiang Province 311121, China
| | - Yusheng Cong
- the Institute of Aging Research, Hangzhou Normal University, School of Medicine, Hangzhou, Zhejiang Province 311121, China
| | - Zhenyu Ju
- the Institute of Aging Research, Hangzhou Normal University, School of Medicine, Hangzhou, Zhejiang Province 311121, China
| | - Dakang Xu
- the Institute of Aging Research, Hangzhou Normal University, School of Medicine, Hangzhou, Zhejiang Province 311121, China, the Hudson Institute of Medical Research, Clayton, Victoria 3168, Australia, the Department of Molecular and Translational Science, Faculty of Medicine, Monash University, Clayton, Victoria 3168, Australia, and
| | - Bryan R G Williams
- the Hudson Institute of Medical Research, Clayton, Victoria 3168, Australia, the Department of Molecular and Translational Science, Faculty of Medicine, Monash University, Clayton, Victoria 3168, Australia, and
| | - Jihui Jia
- From the Department of Microbiology/Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Medicine, Shandong University, Jinan, Shandong Province 250012, China
| | - Jun-Ping Liu
- From the Department of Microbiology/Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Medicine, Shandong University, Jinan, Shandong Province 250012, China, the Institute of Aging Research, Hangzhou Normal University, School of Medicine, Hangzhou, Zhejiang Province 311121, China, the Hudson Institute of Medical Research, Clayton, Victoria 3168, Australia, the Department of Molecular and Translational Science, Faculty of Medicine, Monash University, Clayton, Victoria 3168, Australia, and the Department of Immunology, Faculty of Medicine, Central Clinical School, Monash University, Prahran, Victoria 3018, Australia
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190
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Abstract
DNA damage is correlated with and may drive the ageing process. Neurons in the brain are postmitotic and are excluded from many forms of DNA repair; therefore, neurons are vulnerable to various neurodegenerative diseases. The challenges facing the field are to understand how and when neuronal DNA damage accumulates, how this loss of genomic integrity might serve as a 'time keeper' of nerve cell ageing and why this process manifests itself as different diseases in different individuals.
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Affiliation(s)
- Hei-man Chow
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.,Institute for Advanced Study, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Karl Herrup
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
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191
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Abstract
DNA damage is caused by either endogenous cellular metabolic processes such as hydrolysis, oxidation, alkylation, and DNA base mismatches, or exogenous sources including ultraviolet (UV) light, ionizing radiation, and chemical agents. Damaged DNA that is not properly repaired can lead to genomic instability, driving tumorigenesis. To protect genomic stability, mammalian cells have evolved highly conserved DNA repair mechanisms to remove and repair DNA lesions. Telomeres are composed of long tandem TTAGGG repeats located at the ends of chromosomes. Maintenance of functional telomeres is critical for preventing genome instability. The telomeric sequence possesses unique features that predispose telomeres to a variety of DNA damage induced by environmental genotoxins. This review briefly describes the relevance of excision repair pathways in telomere maintenance, with the focus on base excision repair (BER), nucleotide excision repair (NER), and mismatch repair (MMR). By summarizing current knowledge on excision repair of telomere damage and outlining many unanswered questions, it is our hope to stimulate further interest in a better understanding of excision repair processes at telomeres and in how these processes contribute to telomere maintenance.
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Affiliation(s)
- Pingping Jia
- Elson S. Floyd College of Medicine, United States
| | - Chengtao Her
- School of Molecular Biosciences, Washington State University, United States
| | - Weihang Chai
- Elson S. Floyd College of Medicine, United States; School of Molecular Biosciences, Washington State University, United States.
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192
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Computel: computation of mean telomere length from whole-genome next-generation sequencing data. PLoS One 2015; 10:e0125201. [PMID: 25923330 PMCID: PMC4414351 DOI: 10.1371/journal.pone.0125201] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 03/06/2015] [Indexed: 11/19/2022] Open
Abstract
Telomeres are the ends of eukaryotic chromosomes, consisting of consecutive short repeats that protect chromosome ends from degradation. Telomeres shorten with each cell division, leading to replicative cell senescence. Deregulation of telomere length homeostasis is associated with the development of various age-related diseases and cancers. A number of experimental techniques exist for telomere length measurement; however, until recently, the absence of tools for extracting telomere lengths from high-throughput sequencing data has significantly obscured the association of telomere length with molecular processes in normal and diseased conditions. We have developed Computel, a program in R for computing mean telomere length from whole-genome next-generation sequencing data. Computel is open source, and is freely available at https://github.com/lilit-nersisyan/computel. It utilizes a short-read alignment-based approach and integrates various popular tools for sequencing data analysis. We validated it with synthetic and experimental data, and compared its performance with the previously available software. The results have shown that Computel outperforms existing software in accuracy, independence of results from sequencing conditions, stability against inherent sequencing errors, and better ability to distinguish pure telomeric sequences from interstitial telomeric repeats. By providing a highly reliable methodology for determining telomere lengths from whole-genome sequencing data, Computel should help to elucidate the role of telomeres in cellular health and disease.
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193
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Fleisig HB, Hukezalie KR, Thompson CAH, Au-Yeung TTT, Ludlow AT, Zhao CR, Wong JMY. Telomerase reverse transcriptase expression protects transformed human cells against DNA-damaging agents, and increases tolerance to chromosomal instability. Oncogene 2015; 35:218-27. [PMID: 25893297 DOI: 10.1038/onc.2015.75] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 01/28/2015] [Accepted: 02/06/2015] [Indexed: 12/12/2022]
Abstract
Reactivation of telomerase reverse transcriptase (TERT) expression is found in more than 85% of human cancers. The remaining cancers rely on the alternative lengthening of telomeres (ALT), a recombination-based mechanism for telomere-length maintenance. Prevalence of TERT reactivation over the ALT mechanism was linked to secondary TERT function unrelated to telomere length maintenance. To characterize this non-canonical function, we created a panel of ALT cells with recombinant expression of TERT and TERT variants: TERT-positive ALT cells showed higher tolerance to genotoxic insults compared with their TERT-negative counterparts. We identified telomere synthesis-defective TERT variants that bestowed similar genotoxic stress tolerance, indicating that telomere synthesis activity is dispensable for this survival phenotype. TERT expression improved the kinetics of double-strand chromosome break repair and reduced DNA damage-related nuclear division abnormalities, a phenotype associated with ALT tumors. Despite this reduction in cytological abnormalities, surviving TERT-positive ALT cells were found to have gross chromosomal instabilities. We sorted TERT-positive cells with cytogenetic changes and followed their growth. We found that the chromosome-number changes persisted, and TERT-positive ALT cells surviving genotoxic events propagated through subsequent generations with new chromosome numbers. Our data confirm that telomerase expression protects against double-strand DNA (dsDNA)-damaging events, and show that this protective function is uncoupled from its role in telomere synthesis. TERT expression promotes oncogene-transformed cell growth by reducing the inhibitory effects of cell-intrinsic (telomere attrition) and cell-extrinsic (chemical- or metabolism-induced genotoxic stress) challenges. These data provide the impetus to develop new therapeutic interventions for telomerase-positive cancers through simultaneous targeting of multiple telomerase activities.
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Affiliation(s)
- H B Fleisig
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - K R Hukezalie
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - C A H Thompson
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - T T T Au-Yeung
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - A T Ludlow
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - C R Zhao
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - J M Y Wong
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
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194
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Affiliation(s)
- James W. Larrick
- Panorama Research Institute and Regenerative Sciences Institute, Sunnyvale, California
| | - Andrew R. Mendelsohn
- Panorama Research Institute and Regenerative Sciences Institute, Sunnyvale, California
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195
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Hirashima K, Seimiya H. Telomeric repeat-containing RNA/G-quadruplex-forming sequences cause genome-wide alteration of gene expression in human cancer cells in vivo. Nucleic Acids Res 2015; 43:2022-32. [PMID: 25653161 PMCID: PMC4344506 DOI: 10.1093/nar/gkv063] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Telomere erosion causes cell mortality, suggesting that longer telomeres enable more cell divisions. In telomerase-positive human cancer cells, however, telomeres are often kept shorter than those of surrounding normal tissues. Recently, we showed that cancer cell telomere elongation represses innate immune genes and promotes their differentiation in vivo. This implies that short telomeres contribute to cancer malignancy, but it is unclear how such genetic repression is caused by elongated telomeres. Here, we report that telomeric repeat-containing RNA (TERRA) induces a genome-wide alteration of gene expression in telomere-elongated cancer cells. Using three different cell lines, we found that telomere elongation up-regulates TERRA signal and down-regulates innate immune genes such as STAT1, ISG15 and OAS3 in vivo. Ectopic TERRA oligonucleotides repressed these genes even in cells with short telomeres under three-dimensional culture conditions. This appeared to occur from the action of G-quadruplexes (G4) in TERRA, because control oligonucleotides had no effect and a nontelomeric G4-forming oligonucleotide phenocopied the TERRA oligonucleotide. Telomere elongation and G4-forming oligonucleotides showed similar gene expression signatures. Most of the commonly suppressed genes were involved in the innate immune system and were up-regulated in various cancers. We propose that TERRA G4 counteracts cancer malignancy by suppressing innate immune genes.
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Affiliation(s)
- Kyotaro Hirashima
- Division of Molecular Biotherapy, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, Koto-ku, Tokyo 135-8550, Japan
| | - Hiroyuki Seimiya
- Division of Molecular Biotherapy, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, Koto-ku, Tokyo 135-8550, Japan
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196
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Abstract
The primary purpose of telomeres is to protect chromosome ends from erosion during cell division cycles. In this perspective, Misteli discusses new insight gained from a study by Robin et al. in this issue of Genes & Development demonstrating a novel role for telomeres in gene silencing via formation of long-range chromatin interactions. The primary purpose of telomeres is to protect chromosome ends from erosion during cell division cycles. New observations suggest an additional function for telomeres, namely in gene silencing via formation of long-range chromatin interactions.
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Affiliation(s)
- Tom Misteli
- National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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197
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Ilicheva NV, Podgornaya OI, Voronin AP. Telomere Repeat-Binding Factor 2 Is Responsible for the Telomere Attachment to the Nuclear Membrane. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 101:67-96. [DOI: 10.1016/bs.apcsb.2015.06.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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198
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Zlotorynski E. Chromosome biology: Short telomeres can't reach. Nat Rev Mol Cell Biol 2014; 15:766-7. [PMID: 25415503 DOI: 10.1038/nrm3914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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